This is the exact same DCT found in the M3, 335iS, 135i (N55) , 135iS, & Z435iS

See PDF attachemnt for more specifics and knowledge base. Information collected will be added "progressively". If you find any info missing please post it on this thread, it will be evaluated and will be added to the OP.

DCT Hydraulic Clutch Pressure Data

Quote:

Originally Posted by Page 43

The operating pressure is determined by a regulated control valve depending on the load
and the function selected. The system is protected by a pressure relief valve in the pump.
The pressure is regulated according to the following priorities:
• Clutch engagement and disengagement
• Gear changes
• Cooling the clutch
• Lubrication cycle.
The transmission oil pressure should be high enough to:
• Be able to engage the clutches reliably.
• Allow the gear selector rod to reach the required control shift speed.
The normal operating pressure range is between 5 and 20 bar, although it can be
increased up to 30 bar if necessary to maintain proper transmission operation.
At maximum shifting force, the pressure required to operate the selector rods can be the
same as the operating pressure.
The pressure required for the clutches is limited to 18 bar. The clutch is regulated by an
integrated proportioning valve.
Overpressure protection is ensured by a pressure relief valve.
Clutch cooling is map-controlled using a proportional valve.

The 18 bar clutch pressure limitation is here specific to the M3. Being that the N54 DCT stock torque is significantly more, and launch control RPMs are set to 5k RPMs(static) then the 335iS bar pressure more than likely was increased.

The good news is when we add more power the clutch pressure can be increased to a max of 30 bar via Mechatronics reprograming based on needs

Bar pressure is limited differently per model BMW series cars. So a M3 or a 135i example of clutch slippage will be inaccurate to determine when slippage will occure when adding more power to the N54 DCT (335iS and Z4-35iS)

The PDF attachment also educates when slippage can occure even on a stock DCT car. One prime example is overheating and what the DCT logic does with clutch pressure to cool down the transmission.

Increasing the DCT bar clutch pressure would only be benificial after a clutch pack upgrade while adding more ft-lb,

If slippage is confirmed at 500 wtq during LC, or on dyno, on stock clutches, after the clutch upgrade the slippage will still occure near the same wtq if the bar pressure is not raised.

Example: If definite slippage is confirmed at 500 wtq during LC, WOT, or dyno on stock clutches, after the clutch upgrade the slippage will still occur near the same wtq if the bar pressure is not raised. It will do you no good to raise the bar pressure on stock clutches:

Quote:

Originally Posted by ***********

…… What good is it to have a 3000lb pressure plate if I'm using cardboard for clutch pad material………...

This is a perfect analogy if someone would try to do this, and thus cause severe wear on the stock clutches

DCT slippage has been experienced on tuned and stock N54 DCT. There are multiple reasons why slippage will occur. It does not mean the DCT is weak actually it can take a lot more beating than what people realize

There are safety mechanisms in place that will intervene during performance demands which can result in clutch slippage due to overheating which is the main cause:

There is no difference in the actual DCT GS7D36SG. It is called M - DCT because the M3 version comes with DriveLogic which are selectable "program options" for D, S, and M modes including Launch Control.

The only "hardware" I can recall that is literally different is the DCT output flang that connects to the M3's drive shaft which is different from the N54 DCT output flang.

and the cooler! I guess my main question is i have the dct and i have had a 'heat' related limp mode a couple of times and i was wondering if it was possible to get the cooler and install that on the e92

well i dont have the air/oil cooler and the Tq rating for the m3 and n54 are rather different.

Its not possible for DCT not to have an oil cooler. The oil has to be going somewhere to be cooled. There are oil lines going out and in so the oil cooler must be located in a different place on the N54 DCT vs the M3

This is the exact same DCT found in the M3, 335iS, 135i (N55) , 135iS, & Z435iS

See PDF attachemnt for more specifics and knowledge base. Information collected will be added "progressively". If you find any info missing please post it on this thread, it will be evaluated and will be added to the OP.

DCT Hydraulic Clutch Pressure Data

The 18 bar clutch pressure limitation is here specific to the M3. Being that the N54 DCT stock torque is significantly more, and launch control RPMs are set to 5k RPMs(static) then the 335iS bar pressure more than likely was increased.

The good news is when we add more power the clutch pressure can be increased to a max of 30 bar via Mechatronics reprograming.

Bar pressure is limited differently per model BMW series cars. So a M3 or a 135i example of clutch slippage will be inaccurate to determine when slippage will occure when adding more power to the N54 DCT (335iS and Z4-35iS)

The PDF attachment also educates when slippage can occure even on a stock DCT car. One prime example is overheating and what the DCT logic does with clutch pressure to cool down the transmission.

Increasing the DCT bar clutch pressure would only be benificial after a clutch pack upgrade while adding more ft-lb,

If slippage is confirmed at 500 wtq during LC, or on dyno, on stock clutches, after the clutch upgrade the slippage will still occure near the same wtq if the bar pressure is not raised.

I know my tuner can, but I found a work around and decided not to go down that avenue at this time.

Last time I spoke with the Cobb team they stated its on their road map of things to do:

So they have the ability to increase various pressures...they don't have the ability to reprogram it to accept non-stock clutches though still, correct? It's what caused Drew's SSP clutch pack failure, and I would imagine it's a big part of the reason why Sticky's car has been an expensive paperweight for so long...have there been recent developments allowing the successful application of the SSP packs that I'm not aware of?

So they have the ability to increase various pressures...they don't have the ability to reprogram it to accept non-stock clutches though still, correct? It's what caused Drew's SSP clutch pack failure, and I would imagine it's a big part of the reason why Sticky's car has been an expensive paperweight for so long...have there been recent developments allowing the successful application of the SSP packs that I'm not aware of?

I deleted my previous post, as I thought I was replying to a post talking about LC modification not clutch pack upgrade

Yes, since my tuner does know how to change the RPMs for LC then more than likely they can change the bar pressure in the DCT since its all dealing with the mechatronics.

My last talks with SSP they were looking for a company to reprogram the mechatronics based on their clutch pack "application" ie race only or DD and race.

They were in plans of coming out with a "softer" clutch pack upgrade for DD and race use. The first developed clutch pack was for a pure race application with double or tripple the HP/TQ original output. The stock mechatronics software bar pressure, being stock, would still "slip". So yes, raising the bar pressure is needed to accommodate the new HP/TQ power to prevent slipping

The 335iS would have a smoother and more problem free upgrade to the softer clutch pack upgrade for DD and race applications as the bar pressure is set higher than on the M3

For the record, in my own research I came to this conclusion, it was nothing rumored to me about "HIS" personal business, and nothing was shared with me of such. So my statements are pure speculation.

SSP BMW clutch pack upgrade was not a failure, it was a learning curve, and they have managed to get pass the big bump in the road for "USA car owners"

I deleted my previous post, as I thought I was replying to a post talking about LC modification not clutch pack upgrade

Yes, since my tuner does know how to change the RPMs for LC then more than likely they can change the bar pressure in the DCT since its all dealing with the mechatronics.

My last talks with SSP they were looking for a company to reprogram the mechatronics based on their clutch pack "application" ie race only or DD and race.

They were in plans of coming out with a "softer" clutch pack upgrade for DD and race use. The first developed clutch pack was for a pure race application with double or tripple the HP/TQ original output. The stock mechatronics software bar pressure, being stock, would still "slip". So yes, raising the bar pressure is needed to accommodate the new HP/TQ power to prevent slipping

The 335iS would have a smoother and more problem free upgrade to the softer clutch pack upgrade for DD and race applications as the bar pressure is set higher than on the M3

For the record, in my own research I came to this conclusion, it was nothing rumored to me about "HIS" personal business, and nothing was shared with me of such. So my statements are pure speculation.

SSP BMW clutch pack upgrade was not a failure, it was a learning curve, and they have managed to get pass the big bump in the road for "USA car owners"

Oh by no means was I saying it's a failure. I'm sure the product is a quality piece, it just becomes an expensive paperweight when they can't calibrate the TCU for the new clutches and they die. And while ESS has the ability to modify the pressure on the DCT for faster shifts, etc, as far as I know and understand, they haven't been able to get into the computer far enough to recalibrate it for heavier duty clutches. That said, ESS's abilities definitely seem to be less than super or awesome when venturing far outside the realm of stock design specifications. Perhaps it's something that Renntech can crack.

then why do you have p function in the DCT and its not included the m-dct ??

Like I said before, it is software regulated, managed by the mechatronics controller. I hope you are not mixing the 1st gen DCT with the 2nd gen DCT ? M-DCT is a "drive logic" enhancement that is a software, not hardware. Btw you have the M-DCT in the M6 also, but it is not the same DCT as shared by the M3, 335iS, Z435iS, and the 135i

Very interesting read! Thank you for taking the time to put this together. I was hoping SSP's solution was ready to rock, but I guess not... Until an upgraded clutch pack becomes available, I guess I should focus on seeing if Jake@PTF can change the LC RPMs on my tune, and possibly turn down my boost in 1st gear. With some test runs and adjustments, it would be nice to let the car launch perfectly on its own instead of having to manually launch the car and modulate the throttle. I'm not sure if it's possible to adjust the LC engagement on Cobb yet. I need to look into that.

I don't have problems with my DCT yet, but it would be nice to know upgrade options are available if I end up adding meth to the equation and/or spending more time at the drag strip!